"Consider the project balances for a typical investment project with a service life of four years.

The 'An' for years 0 through 4 are: ($)

-10,000

--

--

2,209

--

The symbol '--' represents missing numbers, not 0.

The project balance at the end of the given years (n = 0 through 4) are: ($)

-10,000

-8,300

-5,500

-4,000

633

Determine the interest rate used in computing the project balance. Enter your answer as a percentage between 0 and 100."